Large aircraft often include turbofan engines enclosed by nacelles. The nacelles comprise a number of rotatable cowls that provide access to the turbofan engines for maintenance. Manual operation of large and heavy cowls presents difficulty for maintenance personnel. Currently, large and heavy engine cowls are operated with the aid of electric or hydraulic powered actuators. Electric powered actuators are powered by an onboard or ground electric power source. Hydraulic powered actuators are powered by electric motor pumps or manually operated pumps, such as hand pumps. These types of systems are a source of added complexity, cost, and maintenance for the aircraft manufacturer and airline. Accordingly, there is a need for purely manually operated systems to facilitate operative opening of large and heavy cowls by maintenance personnel.